Photographic apparatus

ABSTRACT

Mechanical means for separating an image-receiving sheet from a more flexible photo-sensitive sheet after image transfer has occurred, the means comprising two rods around which the more flexible sheet is drawn by a power-driven gripper and around which the less flexible sheet is unable to follow.

United States Patent 1191 [111 3,797,823 Clark Mar. 19, 1974 PHOTOGRAPHIC APPARATUS 2,484.880 10/1949 Flood 271/8 R [76] Inventor: Charles Clark Kmgs 3.461.984 8/1969 Phillips et al. 156/584 x Grove, Maidenhead, Berkshire,

England Filed: Mar. 1972 Primary ExammerR1chard E. Aegerter Appl. No.: 238,122

[30] Foreign Application Priority Data Mar. 29, 1971. Great Britain 8022/71 [52] US. Cl. 271/64, 271/18 R [51] Int. Cl B65h 29/64 [58] Field of Search 271/64, 18 R, 8; 95/13; 221/73; 156/584 [56] References Cited UNITED STATES PATENTS 3166,797 8/1966 Stievenart 271/64 Assistant ExaminerBruce H. Stoner, Jr. Attorney, Agent, or Firm-Brumbaugh, Graves, Donohue & Raymond [57] ABSTRACT Mechanical means for separating an image-receiving sheet from a more flexible photo-sensitive sheet after image transfer has occurred, the means comprising two rods around which the more flexible sheet is drawn by a power-driven gripper and around which the less flexible sheet is unable to follow.

11 Claims, 12 Drawing Figures PATENTEDMAR 1 9 I974 SHEET '4 BF 6 FIG. 7

PATEWEUHKR a 9 IBM SHEET 5 OF 6 776 FEB.

1 PHOTOGRAPHIC APPARATUS This invention relates to photographic apparatus and is concerned with means for handling a film unit of the kind comprising a photosensitive sheet on which a latent image is first formed and an image-receiving sheet on which the final print is formed by a transfer process, one sheet, usually the film, being more flexible than the other.

Film units of this kind and which are self-developing are available in cassettes from Polaroid Corporation of Cambridge, Mass., USA. Each film unit comprises a photosensitive sheet which is exposed by the lens system of the camera to form thereon a latent image and an image-receiving sheet which, during development, is in superposed relation with the photosensitive sheet. The unit also includes a rupturable pod releasably containing a processing liquid which is spread between the contiguous sheets. The imbibition process resulting from this liquid distribution serves to transfer, at least in part, image components from the photosensitive sheet to the'image-receiving sheet which forms the finished photograph.

Hitherto separation of the film and the imagereceiving sheet has been effected by hand but this is troublesome and is particularly unsuitable for automatic photographic apparatus.

According to the present invention photographic apparatus comprises means for moving along the path a composite comprising a photosensitive sheet and an image-receiving sheet superimposed thereon, one sheet being more flexible than the other, and guide means along the path for producing a sharp change in direction for the more flexible of the sheets such that the other tends not to follow and separation is initiated.

The invention is particularly suitable for use in automatic photographic equipment of the kind which is arranged to be brought into operation by actuation of an initiating mechanism and upon such actuation, as by the insertion of a coin in a slot, to apply to a piece of photosensitive sheet material disposed in an exposure position one or more latent images ofa subject occupying an appropriate position, as by being seated on a suitable stool in a sitters compartment, the equipment then causing the production of a final print which is delivered as a finished photograph to the sitter.

The apparatus of the present invention is particularly suitable for use in the automatic photographic apparatus described in my copending Pat. application Nos. 238,071 now US. Pat. No. 3,744,390 and 238,096 now US. Pat. No. 3,744,389 which apparatus comprises a camera, a magazine for cassettes each comprising a number of self-developing film units, transfer means for replacing an expended cassette at the camera by a cassette from the magazine, and means for extracting the film units one by one from the cassette at the camera.

Preferably the moving means comprises a gripper for engaging the leading edge of the photosensitive sheet or a flexible sheet secured thereto and movable along the path. The path is preferably approximately straight, that is a path which is exactly straight or which has only a slight curvature, ahead of the guide means, which is not so great that separation of the film and imagereceiving sheet will occur. The guide means may comprise first and second guides extending across the path and arranged so that the more flexible sheet is deflected around the first guide in order to pass around the second guide. Preferably, at least one of the guides is retractable away from the path.

Either or each of the guides may comprise a transverse guide element such as a bar or roller mounted on one or more swing arms and pivotable towards and away from the path. Where the path is. horizontal, the apparatus preferably includes a first conveyor, such as a belt, located beyond the guide means to receive the more flexible sheet, and a econd conveyor, such as a belt, located below the first conveyor to receive the less flexible sheet. The conveyors may be-arranged to operate in opposite directions so that, for example, the photosensitive sheet may be disposed of and the imagereceiving sheet may be delivered to a collection point.

The invention may be carried into practice in various ways but one particular composite film separation apparatus embodying the present invention will now be described by way of example with reference to the accompanying drawings, in which:

FIGS. 1, 2 and 3 are side, front and bottom elevations respectively of a film pack or cassette of the kind which is to be separated;

FIG. 4 is a somewhat diagrammatic section through a cassette, the cassette shown in FIGS. 1 and 3 containing when full a plurality of film units;

FIG. 5 is an elevation of part of the film handling means;

FIG. 6 is a plan view of the film handling means;

FIG. 7 is an elevation of a stripper mechanism forming part of the film handling means;

FIG. 8 and 9 are views similar to FIG. 7 showing the stripper mechanism in operation to separate a developed print from the backing;

FIG. 10 is a view similar-to FIG. 7 showing an opaque sheet which has been operated upon by the stripper mechanism;

FIG. 11 is a detailed vertical section of the clamps forming part of the film handling means in a position different from that shown in FIGS. 5 and 6; and

FIG. 12 is an elevation of the clamps looking in the direction of an arrow XVII in FIG. 11.

The construction and operation of the apparatus will be outlined in an introduction and the parts of the apparatus and their operation will then be described in detail. It will be appreciated, however, that those parts which are not of direct importance to the invention and those parts which are purely of conventional construction will not be described in detail. For example, details of the drive means, the timing means and the control means which are necessary to cause the apparatus to operate in correct sequence in the manner described will not be set out in detail since their construction and operation can easily be arrived at by those familiar with the art. In addition, descriptions relating to the .photographic portrait cubicle, the cameras, the film cassette handling apparatus, and other details of the complete structure will not be presented since they are fully disclosed in my aforementioned US. Pat. applications, which disclosures are incorporated herein by reference.

As can be seen in FIGS. 1, 2 and 3 each cassette 24 consists of a body 25 having a front wall 26 in which there is a rectangular opening 27, side walls 28, a top wall 29 and-a bottom wall 31 which is only about a third as deep as the side and top walls. The side walls are formed with steps 32 and the cassette is completed by a flat back 33 having, along the two side edges, hooked flanges 34 which slide over the steps 32 to retain the back on the body. Accordingly there is an opening 35 at the bottom end the purpose of which will be described hereafter. Within the cassette there is a separator plate 36 having a smoothly hooked upper end.

When the cassette is full, eight film units are folded around the separator plate 36 and an opaque sheet of paper 38 extends around the film units. The opaque sheet is removed before use and the film units are removed successively as they are exposed. For convenience, FIG. 6 shows only the opaque sheet and a single film unit. Each film unit consists of a flexible sensitized sheet 39 of film, a stiffish transfer or image-receiving sheet 41 to receive the finished photograph, a first connecting strip 42 carrying a pod 43 of developing fluid, a second connecting strip 44, and a narrow leader strip 45. These components are assembled together in the manner shown in FIG. 6, the first connecting position 42 and the second connecting portion 44 being arranged to form a leader tab 46 which is somewhat narrower than the remainder of the unit.

Cassettes of the construction described and containing film units of the construction described are obtainable from the Polaroid Corporation.

It will now be realized that the photographic apparatus consists, apart from the cameras and the control apparatus which will not be described in detail, of two main portions, namely (a) the cassette supply comprising the magazine and the transfer apparatus and (b) the film handling means comprising the film conveying apparatus and the stripping mechanism.

The cassette transfer apparatus is described in detail in my aforementioned Pat. application Ser. No. 238,071.

The film handling means is shown in FIGS. to 12 and includes film conveying apparatus which consists essentially of two clamps to grip the leader strip 45 and the leader tab 46 respectively on an exposed film unit and means for guiding and driving the clamps in the direction of the arrow 87 to draw the film unit from the cassette. The film handling means also includes a stripping mechanism which consists essentially of a pair of guides, one of which is retractable, which engage the film unit as it is drawn out of the cassette.

The film conveying apparatus includes a lower clamp 121 which is mounted on a lower carriage assembly 122. The assembly 122 comprises two guide rods 123 and two bridge pieces 124 and 125 which together form a rectangular frame. Each of the bridge pieces 124 and 125 is provided with guides 126 directly below guide rods 123 so that the carriage assembly 122 can slide on two further guide rods 127 which are fixed to the frame of the apparatus.

An upper clamp 128 is mounted on an upper carriage 129 which is provided with guides 131 so that it can slide on the guide rods 123. I

An electric motor 132 is mounted on the frame of the apparatus, and drives a sprocket 133 by means of a single reduction worm gearbox 134. A roller chain 135 passes around the sprocket 133 and around an idler sprocket 136, situated so that between the sprockets 133 and 136 the chain 135 is parallel to the guide rods 127. A tappet 137 is fixed to the chain 135, which is arranged to move away from the camera on its upper side while the motor 132 is running.

Two thrust members 138 and 139 are mounted on the carriage 129. Each thrust member has a surface adapted to engage the tappet 137; that on thrust member 138 engages it while it is moving towards the camera, while that on thrust member 139 engages it while it is moving away from the camera. The thrust members 138 and 139 are also arranged so that as the tappet 137 passes around either of the sprockets 133 and 136, it disengages from one thrust member, and engages with the other thrust member shortly afterwards. In this way, the carriage 129 can be reciprocated by operating the motor 132. The carriage assembly 122 will also reciprocate over a smaller distance, since it is in effect coupled to the carriage 129 by a lost motion connection.

Two micro-switches (not shown) are mounted on the frame of the apparatus so that their operating levers engage the carriage 129 at certain points in its travel; these allow its motion to be controlled as required.

Each of the clamps 121 and 128 comprises a pair of jaws one of which is spring loaded towards the other. The lower clamp 121 is opened at the end of its travel nearest the camera by a projection 141 which is attached to the frame of the apparatus, and acts on the jaw 142 of the clamp 121; at the other end of its travel, the clamp is held open by a stop 143 which-acts on a lever 144 associated with the clamp 121.

The upper clamp 128 is provided with a latch 145; when the clamp is opened, the latch engages with a projection on the jaw 146 to hold it open. A lever 147 is pivotally attached to the clamp, and engages a stop 148 when the clamp is at the end of its travel furthest from the camera. The jaw 146 is in turn opened by the lever 147. At the other end of its travel the latch 145 engages with a stop 149, which lifts the latch and allows the clamp to close.

Two leaf springs 151 are fixed to the carriage 129 with their ends projecting into the clamp 128 so that when the clamp is open, they ensure that the tab previously gripped by the clamp is ejected.

The stripping mechanism which is shown in detail in FIGS. 7 to 10 is mounted on the frame of the apparatus and comprises a first guide 161 which is fixed and a second guide 162 which can be moved in an arc as shown at 163. To this end, the guide 162 is rotatably mounted on the frame of the apparatus at 164. A crank arm 165 is fixed to the shaft of guide 162. Another shaft 166 is rotatably mounted on the frame of the apparatus and carries a disc 167. A crankpin 168 is attached to the disc 167 and a link 169 connects the crankpin 168 to the crank arm 165. The shaft 166 is driven by an electric motor 171 by means of a gearbox 172, so that by operating the motor 171, the guide 162 can be moved between its extreme positions.

The edge of the disc 167 is cut away over part of its periphery, and a micro-switch is mounted on the frame of the apparatus so that its operating lever presses against the edge of the disc. The switch is arranged as a limit switch for controlling the movement of the guide 162 from one of its extreme positions to the other.

A conveyor belt assembly, consisting of a wide belt 175 passing around two rollers 176 mounted on rotatable shafts 177, is mounted on the frame of the apparatus beneath the position occupied by the lower carriage assembly when it is at its furthest from the camera. Another conveyor belt assembly, consisting of a wide belt 178 passing around two rollers 179 mounted on rotatable shafts 181, is mounted on the frame of the apparatus generally beneath the belt 175. A shaft 182 is rotatably mounted on the frame of the apparatus above the end of the belt 178 nearer the camera and carries a roller 183. Two rollers 184, which are much shorter axially than the roller 183, are rotatably mounted on the frame of the apparatus, one near each end of the roller 183, and with their axes in line and above that of roller 183. A pulley 185 is fixed to one of the shafts 177 supporting the belt 175, and is driven by a driving belt 186 from a pulley 187. Another pulley 188 is integral with the pulley 187, which is rotatably mounted on the frame of the apparatus. Pulleys 189 and 191 are fixed to the shaft 182 and one of the shafts 181 supporting the belt 178 respectively; pulleys 188, 189 and 191 are all driven by a driving belt 192 from a pulley 193, which is driven through a reduction gearbox 194 by an electric motor 195. The motor 195 can be rotated so that the upper surface of belt 175 runs towards the camera and the upper surfaces of belt 178 and roller 183 run away from the camera.

Belts 175 and 178, roller 183, and their driving mechanism, and rollers 184 all form part of the subassembly 11 l The operation of the film conveying and stripping mechanisms will now be described. By operation of the electric motor 132 the carriage 129 is moved towards the camera. After a certain amount of movement, the carriage 129 begins to move the carriage assembly 122 so that they both move towards the camera. During this movement the clamp 128 is open while clamp .121 is closed. When the clamps approach their extreme position nearest the camera, the long leader strip 45 of a film unit in the cassette will enter between the jaws of the upper clamp 128 and as the clamp 128 finally reaches its extreme position near the camera, the latch 145 will engage the stop 149 and the clamp will be triggered shut, gripping the leader strip 45. Also, the clamp 121 will be opened by the projection 141. The electric motor 132 continues to run and moves the carriage 129 away from the camera, drawing the leader strip 45 with it. The leader strip 45' of the following film unit is lightly attached to the leader strip 45, and is unfolded as the leader strip 45 is drawn out. When it is completely unfolded, in preparation for drawing out the following film unit, it becomes detached from the leader strip 45.

Also, as the leader strip 45 is drawn out, the exposed film 39 is drawn around the guide platen upper end 37 of the separator plate 36 until the exposed surface of the film 39 lies against the transfer sheet 41. This also draws the leader tap 46 out of the cassette and this passes between the rollers 104 and then between the jaws of the lower clamp 121, which has not yet moved away from the camera because of the lost motion in the connection between carriages 122 and 129. A spring detent 201 is provided to ensure that the carriage assembly 122 does not begin to move prematurely. When the carriage assembly 122 does begin to move, the projection 141 will no longer hold the clamp 121 open, and the leader tab 46 will be gripped by the clamp. Further movement of the carriages 122 and 129 will cause the lower clamp 121 to draw the entire film unit out of the cassette and will also cause the leader strip 45 to become detached from the connecting strip 42. As the film unit passes between the rollers 104, the pod 43 will be ruptured and the developing fluid contained therein will be spread evenly between the contacting surfaces of the exposed film 39 and the transfer sheet 41. When the leading edge of the film unit reaches the stripping unit, the motor 132 is cut out, the motor 195 is started and the motor 171 is also operated so that the guide 162 is moved from its normal position clear of the film unit into engagement with the film unit. After a delay period, during which the film is held in a dwell position for a length of time appropriate to develop the film and transfer the image to the transfer sheet, the motor 132 restarts and continues to draw the two clamps away from the camera. As can be seen in FIGS. 8 and 9, the film is directed around the rods in such a way that there is a sharp change in direction in its path. The connecting strip 44 is quite flexible and is able to follow this change in direction but the transfer sheet is of fairly stiff material and tends to separate from the backing and to continue along a straight path. Accordingly, the leading edge of the transfer sheet separates from the connecting strip and is guided by fixed guides (not shown) between the roller 183 and the roller 184. FIG. 8 shows the situation just after separation has begun. The rotation of roller 183 tends to move the transfer sheet away from the camera so that it drops onto conveyor belt 178, which delivers it to the print-receiving chute 196 for delivery to the customer.

Shortly before the clamp 121 reaches its extreme position, the lever 144 engages the stop 143 so that the clamp is opened, thereby releasing the leader tab 46. Similarly, when clamp 128 reaches its extreme position, the lever 147 engages the stop 148, so that the clamp is opened. The leader strip 45 is thereby released, and is ejected by the springs 151. The leader strip 45 and leader tab 46 are then carried towards the camera by the conveyor belt 175, and drop between the belt and the stripping unit into the receptacle 72 for disposal.

The motors 132 and are now cut out, and the motor 171 is operated to retract guide 162 to its normal position. This completes the cycle.

Above the position occupied by the film unit during development, a lamp (not shown) is mounted, shining downwards. Below the lamp a photo-transistor (also not shown) is mounted, so that the presence of a film unit between the lamp and the photo-transistor can be detected. If, at the appropriate stage in the cycle, no film unit is detected because of a malfunction or because of a faulty cassette, an alarm signal is actuated, and may be used to indicate to the sitter that there has been a malfunction, and to actuate the cassette handling apparatus to replace the cassette.

Whenever a fresh cassette has been transferred to the camera, the opaque sheet 38 is removed. To do this, the apparatus follows the normal cycle, but without the delay needed for development. The opaque cover sheet is gripped by the upper clamp 128 and drawn out; it passes through the stripping apparatus in the same way as an ordinary film unit, and because of this it is curled to the shape shown in FIG. 12. This ensures that the cover will fall into the receptacle 72 without jamming between the stripper guides and the conveyor belt 175; if the cover were not curled by the stripping apparatus, it would probably jam. The opaque sheet 38 is lightly attached by paste to the leader strip 45 of the first film unit so that as the opaque sheet is drawn out of the cassette the leader strip is unfolded and drawn out. The leader strip 45 separates from the opaque sheet as soon as it is unfolded and the opaque sheet continues without it. This leaves the leader strip in a position ready to be engaged by the upper clamp 121 after the first film unit is exposed.

The way in which the sub-assembly 111 is mounted in the apparatus will now be described. In its normal position, the sub-assembly 111 is located by two dowel pins 112 and supported by four rollers 113 which are rotatably attached to the frame of the apparatus. Each roller supports one of four supporting brackets 114 which are attached to the sub-assembly 111. In the normal position, a horizontal surface of each bracket 114 rests on each roller 113, but when the sub-assembly is removed for maintenance, the dowel pins 112 and the pin 86 disengage, and an inclined surface of each bracket 114 comes into contact with each roller, so that the sub-assembly is lowered as it is withdrawn.

Four pins 115 are attached to the sub-assembly 111, and each engages one of four vertical open ended slots 116 in plates 117. The plates 117 are attached to slide 118, which can slide in the direction of arrow 87 on guide rails 119.

When the sub-assembly is in its normal position, the pins 115 do not touch the bottom of slots 116, but as the sub-assembly is removed, it is lowered until the pins 115 are resting on the bottom of slots 116, so that the sub-assembly is supported on slide 1 18. When the slide 118 has been drawn out to its extreme position, the sub-assembly 111 can easily be removed.

Electrical connections to the apparatus on the subassembly are made by means of a multi-way connector which engages a corresponding connector mounted on the frame of the apparatus. These connectors disengage as the sub-assembly 111 is withdrawn, in the same manner as the dowel pins 112.

The electrical circuits of the apparatus are mounted on another sub-assembly 205, which is mounted on slides 206; the electrical connections to this subassembly are made in a similar manner to those to the sub-assembly 1 11.

.What I claim as my invention and desire to secure by Letter Patent is:

1. In a photographic apparatus utilizing a composite flexible photosensitive sheet and stiff image receiving sheet superimposed thereon, a separating mechanism comprising:

first and second guides;

gripper means for gripping the leading edge of the flexible sheet and drawing the composite along a path between said first and second guides; at least one of said guides being reatively movable from a retracted position in which the guides are spaced apart, to a juxtaposed position in which they are juxtaposed and form a sinuous path around and between said first and second guides;

means for bringing said guides together after passage of the leading edge of the flexible sheet past one of said guides and before passage of the leading edge of the stiff sheet past said one of said guides, thereby to form a sharp curve in said flexible sheet around said sinuous path;

whereby, the stiffness of said stiff sheet will render it unable to follow the sinuous path followed by said flexible sheet and said stiff sheet will separate from said flexible sheet.

2. Apparatus as claimed in claim 1, wherein said gripper means includes a carriage which is slidable along a straight path.

3. Apparatus as defined in claim 1, further comprising means for receiving the separated photosensitive sheet and the image receiving sheet, said receiving means being situated in said apparatus on the downstream side of said guides.

4. Apparatus as defined in claim 1, wherein the path defined between and around said guides, in their juxtaposed position, includes two curves at least one of which is at least 5. Apparatus as defined in claim 1, wherein one of said guides is stationary and the other of said guides is movable;

in the retracted position, the axes of the guides define first a flat plane, and in moving from the retracted position to the juxtaposed position, the axis of the movable guide passes through a second flat plane through and perpendicular to the axis of the stationary guide and perpendicular to said first flat plane.

6. Apparatus as defined in claim 1, wherein:

the axes of said first and second guides, in their retracted position, define a first plane;

the axes of said first and second guides in their juxtaposed position, define a second plane; and

the smallest angle of rotation necessary to bring said first plane parallel to said second plane exceeds 90.

7. A photographic apparatus utilizing a composite sheet including a flexible sheet and a stiff sheet, the flexible sheet having a portion extending forward of the stiff sheet, comprising:

a traveling gripper arranged to grip the leading edge of the flexible sheet and draw the flexible sheet along a path;

first and second guides arranged on opposite sides of said path and between which the composite is drawn by said gripper, at least one of said guides being relatively movable between a retracted position in which the guides are spaced apart far enough to allow the gripper to pass between them, and a closed position in which the guides are juxtaposed and define a sunuous path therebetween around which the flexible sheet is drawn;

whereby the stiffness of the stiff sheet prevents it from following the flexible sheet around the sinuous path so that the stiff sheet and the flexible sheet will separate.

8. Apparatus as defined in claim 7, wherein said path between and around said guides, in the juxtaposed position thereof, includes two curves, at least one of which is at least 90.

9. Apparatus as defined in claim 7, wherein said traveling gripper includes a carriage which is slidable along a straight path.

10. Apparatus as defined in claim 7, wherein one of said guides is stationary and the other of said guides is movable;

in the retracted position, the axes of the guides define a first flat plane, and in moving from the retracted position to the juxtaposed position, the axes of the movable guide passes through a second flat plane through and perpendicular to the axis of the stationary guide and perpendicular to said first flat plane.

11. Apparatus as defined in claim 7, wherein:

the axes of said first and second guides, in their retracted position, define a first plane;

the axes of said first and second guides, in their juxtaposed position, define a second plane; and

the smallest angle of rotation necessary to bring said first plane parallel to said second plane exceeds 90 

1. In a photographic apparatus utilizing a composite flexible photosensitive sheet and stiff image receiving sheet superimposed thereon, a separating mechanism comprising: first and second guides; gripper means for gripping the leAding edge of the flexible sheet and drawing the composite along a path between said first and second guides; at least one of said guides being reatively movable from a retracted position in which the guides are spaced apart, to a juxtaposed position in which they are juxtaposed and form a sinuous path around and between said first and second guides; means for bringing said guides together after passage of the leading edge of the flexible sheet past one of said guides and before passage of the leading edge of the stiff sheet past said one of said guides, thereby to form a sharp curve in said flexible sheet around said sinuous path; whereby, the stiffness of said stiff sheet will render it unable to follow the sinuous path followed by said flexible sheet and said stiff sheet will separate from said flexible sheet.
 2. Apparatus as claimed in claim 1, wherein said gripper means includes a carriage which is slidable along a straight path.
 3. Apparatus as defined in claim 1, further comprising means for receiving the separated photosensitive sheet and the image receiving sheet, said receiving means being situated in said apparatus on the downstream side of said guides.
 4. Apparatus as defined in claim 1, wherein the path defined between and around said guides, in their juxtaposed position, includes two curves at least one of which is at least 90* .
 5. Apparatus as defined in claim 1, wherein one of said guides is stationary and the other of said guides is movable; in the retracted position, the axes of the guides define first a flat plane, and in moving from the retracted position to the juxtaposed position, the axis of the movable guide passes through a second flat plane through and perpendicular to the axis of the stationary guide and perpendicular to said first flat plane.
 6. Apparatus as defined in claim 1, wherein: the axes of said first and second guides, in their retracted position, define a first plane; the axes of said first and second guides in their juxtaposed position, define a second plane; and the smallest angle of rotation necessary to bring said first plane parallel to said second plane exceeds 90* .
 7. A photographic apparatus utilizing a composite sheet including a flexible sheet and a stiff sheet, the flexible sheet having a portion extending forward of the stiff sheet, comprising: a traveling gripper arranged to grip the leading edge of the flexible sheet and draw the flexible sheet along a path; first and second guides arranged on opposite sides of said path and between which the composite is drawn by said gripper, at least one of said guides being relatively movable between a retracted position in which the guides are spaced apart far enough to allow the gripper to pass between them, and a closed position in which the guides are juxtaposed and define a sunuous path therebetween around which the flexible sheet is drawn; whereby the stiffness of the stiff sheet prevents it from following the flexible sheet around the sinuous path so that the stiff sheet and the flexible sheet will separate.
 8. Apparatus as defined in claim 7, wherein said path between and around said guides, in the juxtaposed position thereof, includes two curves, at least one of which is at least 90* .
 9. Apparatus as defined in claim 7, wherein said traveling gripper includes a carriage which is slidable along a straight path.
 10. Apparatus as defined in claim 7, wherein one of said guides is stationary and the other of said guides is movable; in the retracted position, the axes of the guides define a first flat plane, and in moving from the retracted position to the juxtaposed position, the axes of the movable guide passes through a second flat plane through and perpendicular to the axis of the stationary guide and perpendicular to said first flat plane.
 11. Apparatus as defined in claim 7, wherein: the axes of said first and second guides, in their retracted position, define a first Plane; the axes of said first and second guides, in their juxtaposed position, define a second plane; and the smallest angle of rotation necessary to bring said first plane parallel to said second plane exceeds 90* . 